Charles Ellicott Commentary Deuteronomy 15:6

"For Jehovah thy God will bless thee, as he promised thee: and thou shalt lend unto many nations, but thou shalt not borrow; and thou shalt rule over many nations, but they shall not rule over thee." — Deuteronomy 15:6 (ASV)

As he promised you. —I will bless thee was said to Abram (Genesis 12:2).

You shall lend. —The root of the word in Hebrew is closely connected with the word for “slave.” The borrower is servant to the lender (Proverbs 22:7).